2 NEC questions:

[Mike007]

I received a call from a customer. An HVAC job I did failed inspection for 2 issues. The first issue, apparently on the 240V feed to the A/C unit in the panel there is an aluminum ground wire junction-ed to a copper wire with a standard wire nut. The panel was just installed, so I called the electrician who installed it. He told me 1) the standard wire nut is fine because it's not a current carrying conductor. 2) The job passed inspection so it's my problem.

So thats the first question, can an aluminum ground be connected to a copper ground with a standard wire nut as opposed to a purple wire nut for this purpose?

The second issue, there's a service disconnect for the A/C unit on the outside wall. Theres a 6' seal tight whip coming out of the disconnect, it's strapped within 6" of the disconnect. The other end obviously connects to the A/C unit. In between I neatly connected the whip to the refrigerant piping because it looks neater and isn't flopping in the wind.

It failed for "Support liquid tight at condenser independently." Which I can only assume means he wants it loose from the refrigerant piping. Ive done it and seen it done like this 1000's of times without issue.

My second question, is there something in the NEC that would make what I did incorrect?

Thanks.

 

[pattenp]

Not sure about an NEC regulation on the liquid tight being strapped to the refrigerant pipe but the wirenut for the copper to aluminum does need to be specified for the use. NEC 110.14. Being a non current carrying conductor has nothing to do with the requirement.

 

[Mustang51js]

Sounds like the inspector is an *******, but what you could do for the support is a 2x4 or uni strut hit into the ground and strap to that.

 

[C96]

can an aluminum ground be connected to a copper ground with a standard wire nut as opposed to a purple wire nut for this purpose?

Some inspectors just have a pet peeve about splices in panels.
I would ditch the wire nut idea altogether and install a single aluminum ground lug in the panel where the aluminum wire will reach. Scrape a little paint off and screw the lug in place. Install the aluminum wire into the lug with some Noalox Anti Oxidant Compound.

It failed for "Support liquid tight at condenser independently." Which I can only assume means he wants it loose from the refrigerant piping. Ive done it and seen it done like this 1000's of times without issue.

My second question, is there something in the NEC that would make what I did incorrect?

Thanks.

Yes, disconnect it from the refrigerant line as the liquid tight should be supported independently. Then, make sure the liquid tight is strapped within 3’ from the unit. NEC Article 350.30 (A) Exception No. 2 (1)

 

[MTW]

For violations, the inspector is supposed to cite the code sections that are in violation, it's usually best to ask him, rather than a second party with no responsibility to the situation. You can learn much this way and develop a better relationship with him.

Aluminum wire terminations need to be listed for that purpose, usually cu/al listing. Remove the wirenut and connect the wire to the enclosure directly with a ground screw and aluminum lug. this will satisfy the requirement for avoiding dissimilar metals in the connection.

For the whip, the only approved means of support is the structure itself or other items that are specifically listed /approved. The refrigerant lines are not an approved means. Just because everybody does it doesn't make it right.

300.11 Securing and Supporting.
(A) Secured in Place. Raceways, cable assemblies, boxes,
cabinets, and fittings shall be securely fastened in place.
Support wires that do not provide secure support shall not
be permitted as the sole support. Support wires and associated
fittings that provide secure support and that are installed
in addition to the ceiling grid support wires shall be
permitted as the sole support. Where independent support
wires are used, they shall be secured at both ends. Cables
and raceways shall not be supported by ceiling grids.

(B) Raceways Used as Means of Support. Raceways
shall be used only as a means of support for other raceways,
cables, or nonelectrical equipment under any of the
following conditions:
(1) Where the raceway or means of support is identified for
the purpose
(2) Where the raceway contains power supply conductors
for electrically controlled equipment and is used to support
Class 2 circuit conductors or cables that are solely
for the purpose of connection to the equipment control
circuits
(3) Where the raceway is used to support boxes or conduit
bodies in accordance with 314.23 or to support luminaires
in accordance with 410.36(E)

356.30 Securing and Supporting. Type LFNC-B shall be
securely fastened and supported in accordance with one of
the following:
(1) Where installed in lengths exceeding 1.8 m (6 ft), the
conduit shall be securely fastened at intervals not exceeding
900 mm (3 ft) and within 300 mm (12 in.) on
each side of every outlet box, junction box, cabinet, or
fitting.
(2) Securing or supporting of the conduit shall not be required
where it is fished, installed in lengths not exceeding
900 mm (3 ft) at terminals where flexibility is
required, or installed in lengths not exceeding 1.8 m
(6 ft) from a luminaire terminal connection for tap conductors
to luminaires permitted in 410.117(C).
(3) Horizontal runs of LFNC supported by openings through
framing members at intervals not exceeding 900 mm
(3 ft) and securely fastened within 300 mm (12 in.) of
termination points shall be permitted.
(4) Securing or supporting of LFNC-B shall not be required
where installed in lengths not exceeding 1.8 m
(6 ft) from the last point where the raceway is securely
fastened for connections within an accessible ceiling to
luminaire(s) or other equipment.

 

[Norcal]

A copper to aluminum splice is not OK with a standard wire nut, they USED to be listed AL/CU, CU/CU, & AL/AL but not anymore. Strapping to refrigerant lines is not a proper means of support as shown by the NEC text posted by MTW.

BTW the disconnect for the A/C unit is not a "Service Disconnect" a service disconnect, disconnects the service entrance conductors, the @#%&ing HVAC techs have a habit of putting those stickers on safety switches.

 

[Mike007]

I would just take 5 minutes and deal with this, but it's an 80 mile round trip. I talked to the sub code official today. He actually agreed with me the wire nut really shouldn't be my problem since it was inspected and passed just 2 weeks ago. He's going to reach out to the electrician and ask him to return and address it since the guy is local.

As for the other issue with the seal tite, he said he generally passes it. He said it's a whip connecting to an appliance and he doesn't feel it's the same application as using seal tite as a conduit. The homeowner is going to text him a picture of it and if it is as I describe, he will ask his inspector to approve it.

 

[MTW]

For violations, the inspector is supposed to cite the code sections that are in violation, it's usually best to ask him, rather than a second party with no responsibility to the situation. You can learn much this way and develop a better relationship with him.

This usually works good when approached with respect. He agreed with you, that it wasn't your mistake to correct, puts the blame where it belongs, the drive by inspection and lazy contractor.

Mike007, He said it's a whip connecting to an appliance and he doesn't feel it's the same application as using seal tite as a conduit.

Here is a similar response, he agrees with you, common practices. Even though seal-tite (Type LFNC-B) is a conduit type, and has rules as listed above.

Glad to hear you took the right approach and it worked for you. Congrats Ω